Showing papers by "University of North Carolina at Greensboro published in 2013"

Organizational Ambidexterity and Performance: A Meta-Analysis

Abstract: A growing number of studies argue that organizational ambidexterity is increasingly important for the sustained competitive advantage of firms. However, organizational ambidexterity studies have been conducted in a wide variety of industries and methodological settings, and the empirical results have been mixed. The purpose of this article is to systematically examine the organizational ambidexterity–performance relationship to reconcile the mixed results of prior research. By conducting a meta-analysis of prior studies on organizational ambidexterity and performance, we find that positive and significant Organizational ambidexterity–performance relationships are to a large extent moderated by contextual factors and methodological choices: Organizational ambidexterity is particularly important for performance in nonmanufacturing industries and at higher levels of analysis. Also, the performance effects are stronger when “combined” measures of organizational ambidexterity and perceptual performance are use...

No evidence of intelligence improvement after working memory training: A randomized, placebo-controlled study.

Abstract: Numerous recent studies seem to provide evidence for the general intellectual benefits of working memory training. In reviews of the training literature, Shipstead, Redick, and Engle (2010, 2012) argued that the field should treat recent results with a critical eye. Many published working memory training studies suffer from design limitations (no-contact control groups, single measures of cognitive constructs), mixed results (transfer of training gains to some tasks but not others, inconsistent transfer to the same tasks across studies), and lack of theoretical grounding (identifying the mechanisms responsible for observed transfer). The current study compared young adults who received 20 sessions of practice on an adaptive dual n-back program (working memory training group) or an adaptive visual search program (active placebo-control group) with a no-contact control group that received no practice. In addition, all subjects completed pretest, midtest, and posttest sessions comprising multiple measures of fluid intelligence, multitasking, working memory capacity, crystallized intelligence, and perceptual speed. Despite improvements on both the dual n-back and visual search tasks with practice, and despite a high level of statistical power, there was no positive transfer to any of the cognitive ability tests. We discuss these results in the context of previous working memory training research and address issues for future working memory training studies.

Families of Dothideomycetes

Abstract: Dothideomycetes comprise a highly diverse range of fungi characterized mainly by asci with two wall layers (bitunicate asci) and often with fissitunicate dehiscence. Many species are saprobes, with many asexual states comprising important plant pathogens. They are also endophytes, epiphytes, fungicolous, lichenized, or lichenicolous fungi. They occur in terrestrial, freshwater and marine habitats in almost every part of the world. We accept 105 families in Dothideomycetes with the new families Anteagloniaceae, Bambusicolaceae, Biatriosporaceae, Lichenoconiaceae, Muyocopronaceae, Paranectriellaceae, Roussoellaceae, Salsugineaceae, Seynesiopeltidaceae and Thyridariaceae introduced in this paper. Each family is provided with a description and notes, including asexual and asexual states, and if more than one genus is included, the type genus is also characterized. Each family is provided with at least one figure-plate, usually illustrating the type genus, a list of accepted genera, including asexual genera, and a key to these genera. A phylogenetic tree based on four gene combined analysis add support for 64 of the families and 22 orders, including the novel orders, Dyfrolomycetales, Lichenoconiales, Lichenotheliales, Monoblastiales, Natipusillales, Phaeotrichales and Strigulales. The paper is expected to provide a working document on Dothideomycetes which can be modified as new data comes to light. It is hoped that by illustrating types we provide stimulation and interest so that more work is carried out in this remarkable group of fungi.

Urie Bronfenbrenner's Theory of Human Development: Its Evolution From Ecology to Bioecology

Abstract: We describe the evolution, over three phases, of Bronfenbrenner's theory from an ecological to a bioecological theory. Phase 1 (1973–1979) culminated in the publication of The Ecology of Human Development (1979). Phase 2 (1980–1993) saw almost immediate modifications to the theory, with more attention paid to the role of the individual and greater concern with developmental processes. In Phase 3 (1993–2006), proximal processes were defined and placed at the heart of bioecological theory, and from 1998, the Process-Person-Context-Time (PPCT) model was described as the theory's appropriate research design. Given the extent of these changes, and to avoid theoretical incoherence, scholars should be cautious about stating that their research is based on Bronfenbrenner's theory without specifying which version they are using.

Crafting a Future in Science Tracing Middle School Girls’ Identity Work Over Time and Space

Abstract: The underrepresentation of girls from nondominant backgrounds in the sciences and engineering continues despite recent gains in achievement. This longitudinal ethnographic study traces the identity work that girls from nondominant backgrounds do as they engage in science-related activities across school, club, and home during the middle school years. Building a conceptual argument for identity trajectories, the authors discuss the ongoing, cumulative, and contentious nature of identity work and the mechanisms that foster critical shifts in trajectories. The authors argue that the girls view possible future selves in science when their identity work is recognized, supported, and leveraged toward expanded opportunities for engagement in science. This process yields layered meanings of (possible) selves and of science and reconfigures meaningful participation in science.

Physical Activity and Quality of life.

Abstract: Physical activity (PA) professionals and participants recognize enhanced quality of life (QoL) as a benefit of and motivator for PA. However, QoL measures are often problematic and rarely consider the participants'perspective. This paper focuses on recent findings from a larger project on the role of QoL in PA and health promotion. More specifically, we focus on the views of participants and potential participants to better understand the relationship of PA and QoL. In earlier stages of the project we began with a conceptual model of QoL and developed a survey. We now focus on participants' views and ask two questions: 1) what is QoL? and 2) how does PA relate to QoL? We first asked those questions of a large sample of university students and community participants as open-ended survey items, and then asked focus groups of community participants. Overall, participants' responses reflected the multidimensional, integrative QoL model, but the responses and patterns provided information that may not be picked up with typical survey measures. Findings suggest that PA contributes to multiple aspects of QoL, that social and emotional benefits are primary motivators and outcomes for participants, and that the meaning of QoL and PA benefits is subjective and contextualized, varying across individuals and settings. Programs that directly target and highlight the multiple dimensions and integrative QoL, while considering the individual participants and contexts, may enhance both PA motivation and participants' health and QoL.

Desiring a career in STEM‐related fields: How middle school girls articulate and negotiate identities‐in‐practice in science

Abstract: The underrepresentation of non-White students and girls in STEM fields is an ongoing problem that is well documented In K-12 science education, girls, and especially non-White girls, often do not identify with science regardless of test scores In this study, we examine the narrated and embodied identities-in-practice of non-White, middle school girls who articulate future career goals in STEM-related fields For these girls who desire an STEM-related career, we examine the relationships between their narrated and embodied identities-in-practice Drawing on interview and ethnographic data in both school and after school science contexts, we examine how STEM-career minded middle school girls articulate and negotiate a path for themselves through their narratives and actions We present four types of relationships between girls' narrated and embodied identities-in-practice, each with a representative case study: (1) partial overlaps, (2) significant overlaps, (3) contrasting, and (4) transformative The implications of these relationships with regard to both hurdles and support structures that are needed to equip and empower girls in pursuit of their STEM trajectories are discussed © 2013 Wiley Periodicals, Inc J Res Sci Teach 50: 1143-1179, 2013

Urban Form, Air Pollution, and CO2 Emissions in Large U.S. Metropolitan Areas

Abstract: In this article we explore the relationships between urban form and air pollution among 86 U.S. metropolitan areas. Urban form was quantified using preexisting sprawl indexes and spatial metrics applied to remotely sensed land cover data. Air pollution data included the nonpoint source emission of the ozone (O3) precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs), the concentration of O3, the concentration and nonpoint source emission of fine particulate matter (PM2.5), and the emission of carbon dioxide (CO2) from on-road sources. Metropolitan areas that exhibited higher levels of urban sprawl, or sprawl-like urban morphologies, generally exhibited higher concentrations and emissions of air pollution and CO2 when controlling for population, land area, and climate.

Potential metabolite markers of schizophrenia

Abstract: Schizophrenia is a severe mental disorder that affects 0.5–1% of the population worldwide. Current diagnostic methods are based on psychiatric interviews, which are subjective in nature. The lack of disease biomarkers to support objective laboratory tests has been a long-standing bottleneck in the clinical diagnosis and evaluation of schizophrenia. Here we report a global metabolic profiling study involving 112 schizophrenic patients and 110 healthy subjects, who were divided into a training set and a test set, designed to identify metabolite markers. A panel of serum markers consisting of glycerate, eicosenoic acid, β-hydroxybutyrate, pyruvate and cystine was identified as an effective diagnostic tool, achieving an area under the receiver operating characteristic curve (AUC) of 0.945 in the training samples (62 patients and 62 controls) and 0.895 in the test samples (50 patients and 48 controls). Furthermore, a composite panel by the addition of urine β-hydroxybutyrate to the serum panel achieved a more satisfactory accuracy, which reached an AUC of 1 in both the training set and the test set. Multiple fatty acids and ketone bodies were found significantly (P<0.01) elevated in both the serum and urine of patients, suggesting an upregulated fatty acid catabolism, presumably resulting from an insufficiency of glucose supply in the brains of schizophrenia patients.

A targeted metabolomic protocol for short-chain fatty acids and branched-chain amino acids

Abstract: Research in obesity and metabolic disorders that involve intestinal microbiota demands reliable methods for the precise measurement of the short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) concentration. Here, we report a rapid method of simultaneously determining SCFAs and BCAAs in biological samples using propyl chloroformate (PCF) derivatization followed by gas chromatography–mass spectrometry (GC–MS) analysis. A one-step derivatization using 100 μL of PCF in a reaction system of water, propanol, and pyridine (v/v/v = 8:3:2) at pH 8 provided the optimal derivatization efficiency. The best extraction efficiency of the derivatized products was achieved by a two-step extraction with hexane. The method exhibited good derivatization efficiency and recovery for a wide range of concentrations with a low limit of detection for each compound. The relative standard deviations of all targeted compounds showed good intra- and inter-day (within 7 days) precision (<10 %), and good stability (<20 %) within 4 days at room temperature (23–25 °C), or 7 days when stored at −20 °C. We applied our method to measure SCFA and BCAA levels in fecal samples from rats administrated with different diet. Both univariate and multivariate statistical analysis of the concentrations of these targeted metabolites could differentiate three groups with ethanol intervention and different oils in diet. This method was also successfully employed to determine SCFA and BCAA in the feces, plasma and urine from normal humans, providing important baseline information of the concentrations of these metabolites. This novel metabolic profile study has great potential for translational research.

Prediction of Psychopathology and Functional Impairment by Positive and Negative Schizotypy in the Chapmans’ Ten-year Longitudinal Study

Abstract: The present study examined the predictive validity of psychometrically assessed positive and negative schizotypy in the Chapmans’ 10-year longitudinal data set. Schizotypy provides a useful construct for understanding the etiology and development of schizophrenia and related disorders. Schizotypy and schizophrenia share a common multidimensional structure that includes positive and negative symptom dimensions. Recent cross-sectional studies have supported the validity of psychometric positive and negative schizotypy; however, the present study is the first to examine the predictive validity of these dimensions. The Chapmans’ longitudinal data provided an ideal opportunity because of the large sample size, high reassessment rate, and extended interval between assessments. A total of 534 psychometric high-risk and control participants were initially assessed, and 95% of this sample was reinterviewed 10 years later. As hypothesized, positive and negative schizotypy uniquely predicted the development of schizophrenia-spectrum disorders. At the reassessment, both positive and negative schizotypy predicted psychotic-like, schizotypal, and paranoid symptoms, as well as poorer adjustment. The positive dimension was associated with mood and substance use disorders and mental health treatment. Negative schizotypy was associated with schizoid symptoms and social impairment at the follow-up. The results extend the growing validity findings for psychometrically assessed positive and negative schizotypy by demonstrating that they are associated with the development of differential patterns of symptoms and impairment.

Metabonomics identifies serum metabolite markers of colorectal cancer.

Abstract: Recent studies suggest that biofluid-based metabonomics may identify metabolite markers promising for colorectal cancer (CRC) diagnosis We report here a follow-up replication study, after a previous CRC metabonomics study, aiming to identify a distinct serum metabolic signature of CRC with diagnostic potential Serum metabolites from newly diagnosed CRC patients (N = 101) and healthy subjects (N = 102) were profiled using gas chromatography time-of-flight mass spectrometry (GC–TOFMS) and ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC–QTOFMS) Differential metabolites were identified with statistical tests of orthogonal partial least-squares-discriminant analysis (VIP > 1) and the Mann–Whitney U test (p < 005) With a total of 249 annotated serum metabolites, we were able to differentiate CRC patients from the healthy controls using an orthogonal partial least-squares-discriminant analysis (OPLS-DA) in a learning sample set of 62 CRC patients and 62 matched healt

A Global Classroom? Evaluating the Effectiveness of Global Virtual Collaboration as a Teaching Tool in Management Education

Abstract: We evaluate the effectiveness of global virtual student collaboration projects in international management education. Over 6,000 students from nearly 80 universities in 43 countries worked in globa...

Alteration of bile acid metabolism in the rat induced by chronic ethanol consumption

Abstract: Our understanding of the bile acid metabolism is limited by the fact that previous analyses have primarily focused on a selected few circulating bile acids; the bile acid profiles of the liver and gastrointestinal tract pools are rarely investigated. Here, we determined how chronic ethanol consumption altered the bile acids in multiple body compartments (liver, gastrointestinal tract, and serum) of rats. Rats were fed a modified Lieber-DeCarli liquid diet with 38% of calories as ethanol (the amount equivalent of 4-5 drinks in humans). While conjugated bile acids predominated in the liver (98.3%), duodenum (97.8%), and ileum (89.7%), unconjugated bile acids comprised the largest proportion of measured bile acids in serum (81.2%), the cecum (97.7%), and the rectum (97.5%). In particular, taurine-conjugated bile acids were significantly decreased in the liver and gastrointestinal tract of ethanol-treated rats, while unconjugated and glycine-conjugated species increased. Ethanol consumption caused increased expression of genes involved in bile acid biosynthesis, efflux transport, and reduced expression of genes regulating bile acid influx transport in the liver. These results provide an improved understanding of the systemic modulations of bile acid metabolism in mammals through the gut-liver axis.

High-Resolution MS, MS/MS, and UV Database of Fungal Secondary Metabolites as a Dereplication Protocol for Bioactive Natural Products

Abstract: A major problem in the discovery of new biologically active compounds from natural products is the reisolation of known compounds. Such reisolations waste time and resources, distracting chemists from more promising leads. To address this problem, dereplication strategies are needed that enable crude extracts to be screened for the presence of known compounds before isolation efforts are initiated. In a project to identify anticancer drug leads from filamentous fungi, a significant dereplication challenge arises, as the taxonomy of the source materials is rarely known, and, thus, the literature cannot be probed to identify likely known compounds. An ultraperformance liquid chromatography–photodiode array–high-resolution tandem mass spectrometric (UPLC-PDA-HRMS-MS/MS) method was developed for dereplication of fungal secondary metabolites in crude culture extracts. A database was constructed by recording HRMS and MS/MS spectra of fungal metabolites, utilizing both positive- and negative-ionization modes. Ad...

Metaphorically speaking: Cognitive abilities and the production of figurative language.

Abstract: Figurative language is one of the most common expressions of creative behavior in everyday life. However, the cognitive mechanisms behind figures of speech such as metaphors remain largely unexplained. Recent evidence suggests that fluid and executive abilities are important to the generation of conventional and creative metaphors. The present study investigated whether several factors of the Cattell–Horn–Carroll model of intelligence contribute to generating these different types of metaphors. Specifically, the roles of fluid intelligence (Gf), crystallized intelligence (Gc), and broad retrieval ability (Gr) were explored. Participants completed a series of intelligence tests and were asked to produce conventional and creative metaphors. Structural equation modeling was used to assess the contribution of the different factors of intelligence to metaphor production. For creative metaphor, there were large effects of Gf (β = .45) and Gr (β = .52); for conventional metaphor, there was a moderate effect of Gc (β = .30). Creative and conventional metaphors thus appear to be anchored in different patterns of abilities: Creative metaphors rely more on executive processes, whereas conventional metaphors primarily draw from acquired vocabulary knowledge.

Specific Language Impairment

Abstract: The acquisition of language is one of the most important achievements in young children, in part because most children appear to acquire language with little effort. Some children are not so fortunate, however. There is a large group of children who also have difficulty learning language, but do not have obvious neurological, cognitive, sensory, emotional, or environmental deficits. Clinicians often refer to these children as language disordered or language impaired. Researchers tend to refer to these children as specific language impaired (SLI). Children with SLI have intrigued researchers for many years because there is no obvious reason for their language learning difficulties. SLI has been found to be an enduring condition that begins in early childhood and often persists into adolescence and adulthood. The language problems of children with SLI are not limited to spoken language; they also affect reading and writing and thus much of academic learning. Knowledge of the characteristics of SLI should aid physicians, pediatricians, and early childhood specialists to identify these children during the preschool years and ensure that they receive appropriate services. With high-quality language intervention and literacy instruction, most children with SLI should be able to perform and function adequately in school and beyond.

Explanation Feedback Is Better Than Correct Answer Feedback for Promoting Transfer of Learning

Abstract: Among the many factors that influence the efficacy of feedback on learning, the information contained in the feedback message is arguably the most important. One common assumption is that there is a benefit to increasing the complexity of the feedback message beyond providing the correct answer. Surprisingly, studies that have manipulated the content of the feedback message in order to isolate the unique effect of greater complexity have failed to support this assumption. However, the final test in most of these studies consisted of a repetition of the same questions from the initial test. The present research investigated whether feedback that provides an explanation of the correct answer promotes superior transfer of learning to new questions. In 2 experiments, subjects studied prose passages and then took an initial short-answer test on concepts from the text. After each question, they received correct answer feedback, explanation feedback, or no feedback (Experiment 1 only). Two days later, subjects returned for a final test that consisted of both repeated questions and new inference questions. The results showed that correct answer feedback and explanation feedback led to equivalent performance on the repeated questions, but explanation feedback produced superior performance on the new inference questions.

Health survey of U.S. long-haul truck drivers: work environment, physical health, and healthcare access.

Abstract: OBJECTIVE: While trucking in industrialized nations is linked with driver health afflictions, the role of trucking in U.S. truckers' health remains largely unknown. This paper sheds light on links between the trucking work environment and drivers' physical health. METHODS: Using a cross-sectional design, 316 truckers were enrolled in the Healthy Trucker Survey. Questions included work history, physical and mental health, and healthcare access. PASW 18 was used to examine patterns among factors. PARTICIPANTS: 316 truckers participated. RESULTS: Respondents were mainly full-time, long-haul drivers with over 5 years of experience, and who spent over 17 days on the road per month. While almost 75% described their health as good, 83.4% were overweight/obese, 57.9% had sleeping disturbances, 56.3% fatigue, 42.3% musculoskeletal disorders, and about 40% cardiovascular disease concerns. About 33% had no health insurance, 70% had no regular healthcare visits, 24.4% could not afford insurance, and 42.1% took over-the-counter drugs when sick, while 20.1% waited to reach home for medical care. Exercise facilities were unavailable in over 70% of trucking worksites and 70% of drivers did not exercise regularly.CONCLUSIONS: The trucking occupation places drivers at high risk for poor health outcomes. Prospective studies are needed to delve into how continued exposure to trucking influences the progression of disease burden. Language: en

Insulin resistance and the metabolism of branched-chain amino acids

Abstract: Insulin resistance (IR) is a key pathological feature of metabolic syndrome and subsequently causes serious health problems with an increased risk of several common metabolic disorders. IR related metabolic disturbance is not restricted to carbohydrates but impacts global metabolic network. Branched-chain amino acids (BCAAs), namely valine, leucine and isoleucine, are among the nine essential amino acids, accounting for 35% of the essential amino acids in muscle proteins and 40% of the preformed amino acids required by mammals. The BCAAs are particularly responsive to the inhibitory insulin action on amino acid release by skeletal muscle and their metabolism is profoundly altered in insulin resistant conditions and/or insulin deficiency. Although increased circulating BCAA concentration in insulin resistant conditions has been noted for many years and BCAAs have been reported to be involved in the regulation of glucose homeostasis and body weight, it is only recently that BCAAs are found to be closely associated with IR. This review will focus on the recent findings on BCAAs from both epidemic and mechanistic studies.

Melamine-Induced Renal Toxicity Is Mediated by the Gut Microbiota

Abstract: Melamine poisoning has become widely publicized after a recent occurrence of renal injury in infants and children exposed to melamine-tainted milk in China. This renal damage is believed to result from kidney stones formed from melamine and uric acid or from melamine and its cocrystallizing chemical derivative, cyanuric acid. However, the composition of the stones and the mechanism by which the stones are formed in the renal tubules are unknown. We report that cyanuric acid can be produced in the gut by microbial transformation of melamine and serves as an integral component of the kidney stones responsible for melamine-induced renal toxicity in rats. Melamine-induced toxicity in rats was attenuated and melamine excretion increased after antibiotic suppression of gut microbial activity [corrected]. We further demonstrated that melamine is converted to cyanuric acid in vitro by bacteria cultured from normal rat feces; Klebsiella was subsequently identified in fecal samples by 16S ribosomal DNA sequencing. In culture, Klebsiella terrigena was shown to convert melamine to cyanuric acid directly. Rats colonized by K. terrigena showed exacerbated melamine-induced nephrotoxicity. Cyanuric acid was detected in the kidneys of rats administered melamine alone, and the concentration after Klebsiella colonization was increased. These findings suggest that the observed toxicity of melamine may be conditional on the exact composition and metabolic activities of the gut microbiota.

Changing sagittal plane body position during single-leg landings influences the risk of non-contact anterior cruciate ligament injury

Abstract: To examine the effects of different sagittal plane body positions during single-leg landings on biomechanics and muscle activation parameters associated with risk for anterior cruciate ligament (ACL) injury. Twenty participants performed single-leg drop landings onto a force plate using the following landing styles: self-selected, leaning forward (LFL) and upright (URL). Lower extremity and trunk 3D biomechanics and lower extremity muscle activities were recorded using motion analysis and surface electromyography, respectively. Differences in landing styles were examined using 2-way Repeated-measures ANOVAs (sex × landing conditions) followed by Bonferroni pairwise comparisons. Participants demonstrated greater peak vertical ground reaction force, greater peak knee extensor moment, lesser plantar flexion, lesser or no hip extensor moments, and lesser medial and lateral gastrocnemius and lateral quadriceps muscle activations during URL than during LFL. These modifications of lower extremity biomechanics across landing conditions were similar between men and women. Leaning forward while landing appears to protect the ACL by increasing the shock absorption capacity and knee flexion angles and decreasing anterior shear force due to the knee joint compression force and quadriceps muscle activation. Conversely, landing upright appears to be ACL harmful by increasing the post-impact force of landing and quadriceps muscle activity while decreasing knee flexion angles, all of which lead to a greater tibial anterior shear force and ACL loading. ACL injury prevention programmes should include exercise regimens to improve sagittal plane body position control during landing motions.

Assessment of regression kriging for spatial interpolation – comparisons of seven GIS interpolation methods

Abstract: As an important GIS function, spatial interpolation is one of the most often used geographic techniques for spatial query, spatial data visualization, and spatial decision-making processes in GIS and environmental science. However, less attention has been paid on the comparisons of available spatial interpolation methods, although a number of GIS models including inverse distance weighting, spline, radial basis functions, and the typical geostatistical models (i.e. ordinary kriging, universal kriging, and cokriging) are already incorporated in GIS software packages. In this research, the conceptual and methodological aspects of regression kriging and GIS built-in interpolation models and their interpolation performance are compared and evaluated. Regression kriging is the combination of multivariate regression and kriging. It takes into consideration the spatial autocorrelation of the variable of interest, the correlation between the variable of interest and auxiliary variables (e.g., remotely sensed imag...